Walmart Bakery's Cakes

Ok, strange request here. One of my nephew's has a really bad egg and diary allergy. (Eating it breaks him out in a horrible rash and just touching milk will break him out)

He can eat the cakes from Walmart, though. They don't bother him, even when they're not the ones strictly for people with allergies. What is it about the cakes that doesn't cause him to break out? Any ideas?